Everything could always be better, no matter what.
My bet is on you ain't done with it yet.

I don't like what will cause problems first...
the cheap 30A gator clips.  Soldering (with a torch) the wire to the clamp really helps.
the cheap in-line fuse holder. Blade fuses are better for inline, IMHO.

My only power concern is the 1000W inverter feed wire.  1000W is a lot of 12V amps, like 100A.  I can't see anything up to the task, though it might be in there.
Maybe larger wires between batteries, because of the 1000W inverter.

Footnote concerns?  
The loose wire on the roof.  At least fasten it to the 2x4!
The under-PV circulation should be better.  Double up the 2x4s?
Circulation for the inverter heat.

The earlier bare romex remark maybe referes to the left side of the green outlet.

I see a lot of stuff, several years old, done a lot worse, with worse parts, often in damp or dusty places, and the connections are the usual problem.